/*
 * Copyright 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*namespace com.google.zxing.qrcode.encoder {*/

import ByteMatrix from './ByteMatrix'
import Exception from './../../Exception'

/**
 * @author Satoru Takabayashi
 * @author Daniel Switkin
 * @author Sean Owen
 */
export default class MaskUtil {

  // Penalty weights from section 6.8.2.1
  private static N1 = 3;
  private static N2 = 3;
  private static N3 = 40;
  private static N4 = 10;

  private constructor() {
    // do nothing
  }

  /**
   * Apply mask penalty rule 1 and return the penalty. Find repetitive cells with the same color and
   * give penalty to them. Example: 00000 or 11111.
   */
  public static applyMaskPenaltyRule1(matrix: ByteMatrix): number /*int*/ {
    return MaskUtil.applyMaskPenaltyRule1Internal(matrix, true) + MaskUtil.applyMaskPenaltyRule1Internal(matrix, false)
  }

  /**
   * Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
   * penalty to them. This is actually equivalent to the spec's rule, which is to find MxN blocks and give a
   * penalty proportional to (M-1)x(N-1), because this is the number of 2x2 blocks inside such a block.
   */
  public static applyMaskPenaltyRule2(matrix: ByteMatrix): number /*int*/ {
    let penalty = 0
    const array: Array<Uint8Array> = matrix.getArray()
    const width: number /*int*/ = matrix.getWidth();
    const height: number /*int*/ = matrix.getHeight();
    for (let y = 0; y < height - 1; y++) {
      const arrayY = array[y]
      for (let x = 0; x < width - 1; x++) {
        const value = arrayY[x]
        if (value === arrayY[x + 1] && value === array[y + 1][x] && value === array[y + 1][x + 1]) {
          penalty++
        }
      }
    }
    return MaskUtil.N2 * penalty;
  }

  /**
   * Apply mask penalty rule 3 and return the penalty. Find consecutive runs of 1:1:3:1:1:4
   * starting with black, or 4:1:1:3:1:1 starting with white, and give penalty to them.  If we
   * find patterns like 000010111010000, we give penalty once.
   */
  public static applyMaskPenaltyRule3(matrix: ByteMatrix): number /*int*/ {
    let numPenalties = 0
    const array: Array<Uint8Array> = matrix.getArray()
    const width: number /*int*/ = matrix.getWidth();
    const height: number /*int*/ = matrix.getHeight();
    for (let y = 0; y < height; y++) {
      for (let x = 0; x < width; x++) {
        const arrayY: Uint8Array = array[y];  // We can at least optimize this access
        if (x + 6 < width &&
            arrayY[x] === 1 &&
            arrayY[x + 1] === 0 &&
            arrayY[x + 2] === 1 &&
            arrayY[x + 3] === 1 &&
            arrayY[x + 4] === 1 &&
            arrayY[x + 5] === 0 &&
            arrayY[x + 6] === 1 &&
            (MaskUtil.isWhiteHorizontal(arrayY, x - 4, x) || MaskUtil.isWhiteHorizontal(arrayY, x + 7, x + 11))) {
          numPenalties++
        }
        if (y + 6 < height &&
            array[y][x] === 1 &&
            array[y + 1][x] === 0 &&
            array[y + 2][x] === 1 &&
            array[y + 3][x] === 1 &&
            array[y + 4][x] === 1 &&
            array[y + 5][x] === 0 &&
            array[y + 6][x] === 1 &&
            (MaskUtil.isWhiteVertical(array, x, y - 4, y) || MaskUtil.isWhiteVertical(array, x, y + 7, y + 11))) {
          numPenalties++
        }
      }
    }
    return numPenalties * MaskUtil.N3
  }

  private static isWhiteHorizontal(rowArray: Uint8Array, from: number /*int*/, to: number /*int*/): boolean {
    from = Math.max(from, 0)
    to = Math.min(to, rowArray.length)
    for (let i = from; i < to; i++) {
      if (rowArray[i] === 1) {
        return false
      }
    }
    return true
  }

  private static isWhiteVertical(array: Uint8Array[], col: number /*int*/, from: number /*int*/, to: number /*int*/): boolean {
    from = Math.max(from, 0)
    to = Math.min(to, array.length)
    for (let i = from; i < to; i++) {
      if (array[i][col] === 1) {
        return false
      }
    }
    return true
  }

  /**
   * Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
   * penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance.
   */
  public static applyMaskPenaltyRule4(matrix: ByteMatrix): number /*int*/ {
    let numDarkCells = 0
    const array: Array<Uint8Array> = matrix.getArray()
    const width: number /*int*/ = matrix.getWidth();
    const height: number /*int*/ = matrix.getHeight();
    for (let y = 0; y < height; y++) {
      const arrayY: Uint8Array = array[y]
      for (let x = 0; x < width; x++) {
        if (arrayY[x] === 1) {
          numDarkCells++
        }
      }
    }
    const numTotalCells = matrix.getHeight() * matrix.getWidth();
    const fivePercentVariances = Math.floor(Math.abs(numDarkCells * 2 - numTotalCells) * 10 / numTotalCells)
    return fivePercentVariances * MaskUtil.N4;
  }

  /**
   * Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
   * pattern conditions.
   */
  public static getDataMaskBit(maskPattern: number /*int*/, x: number /*int*/, y: number /*int*/): boolean {
    let intermediate: number /*int*/
    let temp: number /*int*/
    switch (maskPattern) {
      case 0:
        intermediate = (y + x) & 0x1
        break
      case 1:
        intermediate = y & 0x1
        break
      case 2:
        intermediate = x % 3
        break
      case 3:
        intermediate = (y + x) % 3
        break
      case 4:
        intermediate = (Math.floor(y / 2) + Math.floor(x / 3)) & 0x1
        break
      case 5:
        temp = y * x;
        intermediate = (temp & 0x1) + (temp % 3)
        break
      case 6:
        temp = y * x;
        intermediate = ((temp & 0x1) + (temp % 3)) & 0x1
        break
      case 7:
        temp = y * x;
        intermediate = ((temp % 3) + ((y + x) & 0x1)) & 0x1
        break
      default:
        throw new Exception(Exception.IllegalArgumentException, "Invalid mask pattern: " + maskPattern)
    }
    return intermediate === 0
  }

  /**
   * Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
   * vertical and horizontal orders respectively.
   */
  private static applyMaskPenaltyRule1Internal(matrix: ByteMatrix, isHorizontal: boolean): number /*int*/ {
    let penalty = 0
    const iLimit = isHorizontal ? matrix.getHeight() : matrix.getWidth()
    const jLimit = isHorizontal ? matrix.getWidth() : matrix.getHeight()
    const array: Array<Uint8Array> = matrix.getArray()
    for (let i = 0; i < iLimit; i++) {
      let numSameBitCells = 0
      let prevBit = -1
      for (let j = 0; j < jLimit; j++) {
        const bit = isHorizontal ? array[i][j] : array[j][i]
        if (bit == prevBit) {
          numSameBitCells++
        } else {
          if (numSameBitCells >= 5) {
            penalty += MaskUtil.N1 + (numSameBitCells - 5)
          }
          numSameBitCells = 1;  // Include the cell itself.
          prevBit = bit
        }
      }
      if (numSameBitCells >= 5) {
        penalty += MaskUtil.N1 + (numSameBitCells - 5)
      }
    }
    return penalty
  }

}
